U.S. patent application number 11/299078 was filed with the patent office on 2007-01-18 for sheet alignment apparatus and sheet finisher provided therewith.
Invention is credited to Hisao Hosoya, Tsuyoshi Mizubata, Satoru Shimizu, Tsuyoshi Shiokawa.
Application Number | 20070013126 11/299078 |
Document ID | / |
Family ID | 37660972 |
Filed Date | 2007-01-18 |
United States Patent
Application |
20070013126 |
Kind Code |
A1 |
Mizubata; Tsuyoshi ; et
al. |
January 18, 2007 |
Sheet alignment apparatus and sheet finisher provided therewith
Abstract
A sheet alignment apparatus includes: an aligning element for
pushing a sheet supported on a sheet supporting face by moving in a
direction perpendicular to a conveyance direction of the sheet,
thereby aligning a position of the sheet; and a driving source for
reciprocating the aligning element. An aligning face of the
aligning element is arranged to be inclined with respect to the
sheet supporting face.
Inventors: |
Mizubata; Tsuyoshi; (Tokyo,
JP) ; Hosoya; Hisao; (Sagamihara-shi, JP) ;
Shimizu; Satoru; (Tokyo, JP) ; Shiokawa;
Tsuyoshi; (Tokyo, JP) |
Correspondence
Address: |
SQUIRE, SANDERS & DEMPSEY L.L.P.
1 MARITIME PLAZA, SUITE 300
SAN FRANCISCO
CA
94111
US
|
Family ID: |
37660972 |
Appl. No.: |
11/299078 |
Filed: |
December 8, 2005 |
Current U.S.
Class: |
271/238 |
Current CPC
Class: |
B65H 2701/1315 20130101;
B65H 31/34 20130101; B65H 2301/36212 20130101; B65H 2405/114
20130101 |
Class at
Publication: |
271/238 |
International
Class: |
B65H 9/00 20060101
B65H009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2005 |
JP |
JP2005-206853 |
Claims
1. A sheet alignment apparatus comprising: (a) an aligning element
for pushing edges of a sheet supported on a sheet supporting face
by moving in a direction perpendicular to a conveyance direction of
the sheet, thereby aligning a position of the sheet; and (b) a
driving source for reciprocating the aligning element, wherein an
aligning face of the aligning element is arranged to be inclined
with respect to the sheet supporting face.
2. The sheet alignment apparatus of claim 1, wherein a part of the
aligning face has an acute angel with respect to the sheet
supporting face on a side of the sheet.
3. The sheet alignment apparatus of claim 1, wherein the aligning
face is formed by a flat surface.
4. The sheet alignment apparatus of claim 1, wherein the aligning
face is formed by a curved surface.
5. A sheet finisher comprising: (a) an aligning element for pushing
edges of a sheet supported on a sheet supporting face by moving in
a direction perpendicular to a conveyance direction of the sheet,
thereby aligning a position of the sheet; (b) a driving source for
reciprocating the aligning element; and (c) a supporting table
having the sheet supporting face being inclined by 60.degree. or
more with respect to a horizon, wherein an aligning face of the
aligning element is arranged to be inclined with respect to the
sheet supporting face.
6. The sheet finisher of claim 5, further comprising a binding unit
for binding a sheet bundle on the supporting table.
Description
[0001] This application is based on Japanese Patent Application No.
2005-206853 filed on Jul. 15, 2005, which is incorporated hereinto
by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a sheet alignment apparatus
for aligning a sheet-like paper and a sheet finisher provided with
the sheet alignment apparatus.
[0003] For paper with an image formed thereon, an high-speed image
forming apparatus such as an electrophotographic image forming
apparatus is often used in combination with a sheet finisher that
provides finishing operations such as stapling, punching, folding
and shifting. The sheet finisher is commonly equipped with a sheet
stacking apparatus for stacking a plurality of sheets are stacked
to form a bundle of paper.
[0004] In many cases, the sheet stacking apparatus is required to
have a function of stacking sheets by aligning the edge of each
sheet or a plurality of sheets being fed, in both the lateral and
longitudinal directions. The sheet stacking apparatus has a sheet
alignment apparatus for aligning the edges in the lateral and
longitudinal directions, i.e. the edges in the conveying direction
of the paper being introduced, and the edge across the width of
paper.
[0005] As disclosed in the Patent Document 1, the sheet alignment
apparatus includes an aligning element for aligning the lateral
edge of paper by making a reciprocating motion in the direction
intersecting the conveying direction when paper is introduced into
the sheet stacking apparatus and a stopper for receiving the
leading edge of paper when it is introduced. It aligns the paper
falling from a inclined supporting table, in the lateral and
longitudinal directions.
[0006] [Patent Document 1]: the Official Gazette of Japanese
non-examined Patent Publication No. 10-297815.
[0007] The following describes the conventional sheet alignment
apparatus with reference to FIG. 6.
[0008] The sheet alignment apparatus has a supporting table SD for
supporting the sheet and aligning elements SG1 and SG2 for aligning
the sheet. Sheets S are stacked on the supporting table SD. Every
time the sheet S is introduced, the aligning elements SG1 and SG2
make a reciprocating motion opposite to each other in the X
direction so as to align the lateral edges of the sheets S. When
the stacked sheets are curled, the sheets S close to the bottom of
the bundle of sheets S are formed flat due to the weight of sheets
S. However, the sheets S on the upper portion are not pressed from
the top, and therefore, the force for correcting the curl is
reduced or the correcting force does not work, with the result that
the curl of sheets S is kept uncorrected at the time of
introduction.
[0009] Thus, the apparent length Lb of the sheets on the upper
portion is smaller than the apparent length La of the sheets closer
to the bottom. To be more specific, the sheet contour line SRS
formed by connecting the edges of the sheets S is inclined with
respect to the aligning line SGS drawn on the aligning face of the
aligning element SG1. The spacing between the aligning line SGS and
sheet contour line SRS is greater at a higher position.
[0010] As a result, alignment effects of the aligning elements SG1
and SG2 are reduced at a higher position. Thus, the alignment of
the edges of sheets tends to become more difficult due to reduced
alignment performances.
[0011] FIG. 6 shows an example of an upward curl wherein the
central portion of sheet S is curled upward. This is the same as
the downward curl wherein the central portion of sheet S is curled
downward, in that the apparent length of the sheet S is smaller as
the degree of curling is greater. The sheet contour line SRS is
more removed from the perpendicular aligning line SGS at a higher
position.
SUMMARY OF THE INVENTION
[0012] The present invention is characterized by one of the
following structures:
[0013] 1. A sheet alignment apparatus comprising: an aligning
element for pushing edges of a sheet supported on a sheet
supporting face by moving in a direction perpendicular to a
conveyance direction of the sheet, thereby aligning a position of
the sheet; and a driving source for reciprocating the aligning
element, wherein an aligning face of the aligning element is
arranged to be inclined with respect to the sheet supporting
face.
[0014] 2. A sheet finisher comprising: an aligning element for
pushing edges of a sheet supported on a sheet supporting face by
moving in a direction perpendicular to a conveyance direction of
the sheet, thereby aligning a position of the sheet position; a
driving source for reciprocating the aligning element; and a
supporting table having the sheet supporting face being inclined by
60.degree. or more with respect to a horizon, wherein an aligning
face of the aligning element is arranged to be inclined with
respect to the sheet supporting face.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is an overall block diagram representing an image
forming apparatus incorporating a sheet alignment apparatus and
sheet finisher as an embodiment of the present invention;
[0016] FIG. 2 is a diagram showing the major portions of the sheet
finisher as an embodiment of the present invention;
[0017] FIG. 3 is a plan of the sheet alignment apparatus as an
embodiment of the present invention;
[0018] FIG. 4 is a cross sectional view showing an example of the
aligning element;
[0019] FIG. 5 is a cross sectional view showing another example of
the aligning element; and
[0020] FIG. 6 is a cross sectional view of a conventional aligning
element.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] The following describes the present invention with reference
to the embodiments shown in the drawings, without the present
invention being restricted thereto.
<Image Forming Apparatus>
[0022] FIG. 1 is an overall block diagram representing an image
forming apparatus incorporating a sheet finisher as an embodiment
of the present invention.
[0023] The image forming apparatus main body A has an image forming
section GK in which a charger 2, an imagewise exposing unit 3, a
developing unit 4, a transfer unit SA, a discharger SB, a
separation claw 5C and a cleaning unit 6 are arranged around a
photoreceptor 1. After the surface of the photoreceptor 1 has been
uniformly charged by the charger 2, a latent image is formed by
exposure based on the image data obtained by reading the document
Ge to be copied by the light beam of the imagewise exposing unit 3
or the image data received from the outside through a network. The
latent image is subjected to reversal development by the developing
unit 4, whereby a toner image is formed on the surface of the
photoreceptor 1.
[0024] The recording-sheet RS fed from the sheet feed tray 7A as a
sheet feeding and storing unit is fed to the transfer position,
where the toner image is transferred onto the recording sheet RS by
the transfer unit 5A. Then the electric charge on the back side of
the recording sheet RS is removed by the discharger 5B. The
recording sheet RS is removed from the photoreceptor 1 by the
separation claw 5C, and is conveyed by the intermediate conveyance
unit 7B. Then the recording sheet RS is subjected to the process of
fixing by a fixing unit 8, and is ejected by an ejection roller
7C.
[0025] When an image is formed on one side of the recording sheet
RS, a conveyance path switching board 7D as one of the sheet
conveyance units is switched over to the position indicated by a
dotted line.
[0026] Downstream of the separation claw 5C, the remaining
developer, i.e. toner is removed by the cleaning unit 6 from the
surface of the photoreceptor 1 subsequent to image formation,
thereby creating a required environment for next image
formation.
[0027] When an image is formed on both sides of the recording sheet
RS, the conveyance path switching board 7D is switched over to the
position indicated by the dotted line. Then the recording sheet RS
having been heated and fixed by the fixing unit 8 is conveyed
downward and is switched back by the sheet reversing and conveying
unit 7E so that the recording sheet RS is reversed. After that, a
new toner image is transferred on the back face at the transfer
position.
[0028] As will be described later, when punching, folding, binding
and others operations are performed, the conveyance path switching
board 7D is switched to the position indicated by the solid line,
whereby the recording sheet RS having been heated and fixed by the
fixing unit 8 is fed downward and is switched back by the sheet
reversing and conveying unit 7E so that the recording sheet RS is
reversed. After that, the sheets are fed upward with the trailing
edges becoming the leading edges, and are ejected by the ejection
roller 7C.
[0029] The recording sheet RS ejected from the ejection roller 7C
is fed to the first sheet finisher FS1.
[0030] An operation display unit 9 capable of selecting and setting
various forms of modes such as an image formation mode and sheet
finishing mode is arranged on the stop front side of the image
forming apparatus main body A. An image reading apparatus B as an
image reading unit equipped with an automatic document conveyance
apparatus G is mounted on the upper portion of the image forming
apparatus main body A. The image data obtained from reading by the
image reading apparatus B and the image data received from outside
by facsimile machine or network communication are stored in the
storage apparatus (not illustrated).
[0031] The first sheet finisher FS1 is a sheet finishing apparatus
for punching and folding. The second sheet finisher FS2 is a sheet
finishing apparatus for shifting and binding.
[0032] The first sheet finisher FS1 has a punching unit 12 and a
folding unit 14. The recording sheet RS ejected from the image
forming apparatus main body A and the cover HS supplied from the
cover feed tray 11 are subjected to the process of punching and
folding at the inlet. 10.
[0033] As illustrated, the folding unit 14 has several branched
conveyance paths. Folding in two or folding in three can be
performed by proper selection of branched conveyance paths.
[0034] A fixed ejection tray 30 used a sub-tray is arranged in the
upper tray of the second sheet finisher FS2. A shifting unit 50 and
ejecting unit 60 are provided along an approximately horizontal
conveyance path h2. A binding unit 70 and a folding unit 80 are
provided in the lower tray of the second sheet finisher FS2.
[0035] A main tray 90 for loading the shifted sheets and stapled
bundles of paper is arranged on the left inside the second sheet
finisher FS2. A lower tray 91 is mounted on the lower left, and
folded sheets are ejected in this tray.
[0036] The following describes the structure of the second sheet
finisher FS2 with reference to FIGS. 1 through 4. FIG. 2 is a
diagram showing the major portions of the second sheet finisher
FS2. FIG. 3 is a plan of the sheet alignment apparatus as an
embodiment of the present invention, and FIG. 4 is a cross
sectional view showing an example of the aligning element. In the
following description, the recording sheet RS and cover HS will be
collectively called the sheet S.
[0037] The sheet S ejected from the first sheet finisher FS1 is led
to the inlet 20 of the second sheet finisher FS2.
[0038] A sheet branching unit composed of switching gates G1 and G2
is provided downstream of the inlet 20. Driven by a solenoid (not
illustrated)., the switching gates G1 and G2 selects one of the
three conveyance paths, i.e. a first conveyance path h1 for the
upper tray ejection, a second conveyance path h2 for the middle
tray ejection and a third conveyance path h3 for the lower tray
ejection.
[0039] In the image formation on a small number of sheets, the
switching gate G1 opens only the first conveyance path h1, closing
the second conveyance path h2 and third conveyance path h3. The
sheets S are fed along the first conveyance path h1. Gripped by the
conveyance roller 31 located downstream, the sheets S go upward,
and are ejected by an ejection roller 32. They are then stacked on
the sub tray 30 sequentially.
[0040] The sub tray 30 has a storage capacity of accommodating a
maximum of 200 sheets S.
[0041] In a large volume image formation mode where stapling is not
performed, the switching gate G1 blocks the first conveyance path
h1. The switching gate G2 closes the third conveyance path h3, and
opens the second conveyance path h2 to allow the sheet S to be fed.
Guiding the sheet S, it allows the sheet S to be ejected to the
main tray 90. In the mode wherein the sheet S is ejected to the
main tray 90 through the second conveyance path h2, the sheet S can
be shifted by the shifting unit 50. The shifting unit 50 applies
processing of shifting, whereby the ejection position of the sheet
S is shifted across the width every predetermined number of sheets.
The main tray 90 is lowered when a large number of sheets S are to
be stacked. A maximum of 3000 sheets can be stored in the case of
A4-sized or B5-sized paper.
[0042] A sheet sensor PS1 for sensing the passage of the sheet S
ejected to the main tray 90 is provided in the vicinity of the
ejection roller 61 constituting the ejecting unit 60.
[0043] The sheet S ejected from the first sheet finisher FS1 is fed
along the third conveyance path h3 by the conveyance rollers 22 and
23. The sheet S is fed upward on the left over an intermediate
stacker 71 by a stacker ejection roller 24. The trailing edge of
the sheet S passes through the stacker ejection roller 24. The
sheet S is detached from the stacker ejection roller 24 and is
dropped onto the intermediate stacker 71 by gravity.
[0044] The intermediate stacker 71 is a supporting table for
support the sheets S. A sheet supporting face of the supporting
table is inclined by angle .theta. with respect to the horizontal
line HL. To improve the performance of aligning the leading edge of
the sheet S and to downsize the apparatus, the angle is preferably
.theta..gtoreq.60.degree..
[0045] When the bottom edge of the sheet S has reached the stopper
72, a pair of aligning elements 73A and 73B make a reciprocating
motion across the width intersecting the conveying direction of the
sheet S, i.e. in the X direction, whereby the sheets S are aligned
across the width (FIGS. 3 and 4). Further, the lower ends of the
sheets S are aligned by the stopper 72.
[0046] The aforementioned processing is applied on a continuous
basis to the sheets S supplied to the intermediate stacker 71. A
predetermined number of aligned sheets S are stacked on the
intermediate stacker 71.
[0047] When a predetermined number of sheets S have been stacked,
the binding unit 70 operates to bind a bundle of sheets S.
[0048] When the binding has terminated, the stopper 72 is fed
upward by the belt 74 driven by the motor Ml obliquely to the left
in FIGS. 1 and 2, whereby the bundle of sheets S is pushed upward
and is ejected to the main tray 90.
[0049] The bundle of sheets S stacked in the intermediate stacker
71 is again fed obliquely to the bottom. The sheets S are folded by
the folding unit 80 and are ejected to the lower tray 91.
<Alignment of Sheet>
[0050] The alignment of sheets will be described with reference to
FIGS. 2 through 5. FIG. 5 is a cross sectional view showing another
example of the aligning element.
[0051] The aligning elements 73A and 73B are fixed to the belt 74
driven by the motor M2 as a driving source. They makes a
reciprocating motion in the direction opposite to each other caused
by the forward and reverse rotation of the motor M2, whereby the
sheets S are aligned.
[0052] As shown in FIG. 4, the aligning element 73A is U-shaped,
and is composed of an upper plate unit 73A1, a side plate unit 73A2
and a lower plate unit 73A3. The aligning element 73B is also
U-shaped and is composed of an upper plate unit 73B1, a side plate
unit 73B2 and a lower plate unit 73B3. The left side of the side
plate unit 73A2 and the right side of the side plate unit 73B2 are
used to align the lateral edge of the sheet S as aligning faces.
The side plate unit 73A2 and side plate unit 73B2 are brought into
contact with the lateral edge of the sheets S, whereby the sheets S
are aligned.
[0053] The intermediate stacker 71 as a supporting table for
supporting the sheet S constitutes the sheet supporting face JS
that supports the sheet S. The sheets S are stacked on the
intermediate stacker 71 and are loaded approximately parallel to
the sheet supporting face JS. When a large number of sheets S have
been loaded, the sheets S are loaded in a flat form on the lower
portion by gravity, but the upper portion of the sheets is curled
as illustrated. In this case, the sheets S are stacked in a curled
form.
[0054] The aligning surface of the side plate unit 73A2, i.e. the
left surface of the side plate unit 73A2 is formed to be deviated
by an inclined angle of .alpha.1 toward the sheet from the
direction PJS orthogonal to the sheet supporting face JS. The
inclined angle .alpha.1 is formed along the sheet contour line SRS
which is formed by a large number of curled sheets S.
[0055] The sheet contour line SRS assume varied angles depending on
the degree of the curl of the sheet S. The inclined angle .alpha.1
is set to the average value of various angles or a value close
thereto.
[0056] In the similar manner, the side plate unit 73B2 is formed in
such a way that the aligning surface, i.e. the right side of the
side plate unit 73B2 is deviated by an inclined angle of .alpha.2
toward the sheet from the direction PJS orthogonal to the sheet
supporting face JS.
[0057] The inclined angles .alpha.1 and .alpha.2 are preferably
0.5.degree. through 1.5.degree..
[0058] If the inclined angles .alpha.1 and .alpha.2 are smaller
than 0.5.degree., the performance of aligning the curled paper will
be reduced. If the inclined angles .alpha.1 and .alpha.2 are
greater than 1.5.degree., then a sheet bending force will be
applied to the sheets if they are flat and uncurled. This will
cause the sheets to be bulged, and alignment performance will be
reduced.
[0059] If the side plate units 73A2 and 73B2 are formed as
described above, both curled and uncurled sheets are aligned
correctly.
[0060] FIG. 5 is a cross sectional view showing another example of
the aligning element.
[0061] As shown in FIG. 5, the aligning surfaces of the side plate
units 73A2 and 73B2 are positioned at right angles with the sheet
supporting surface JS, on the lower portion. On the upper portion,
they are inclined toward the sheet S. The example shown in FIG. 5
exhibits excellent alignment performances for the curled
sheets.
[0062] The aforementioned embodiments provide a sheet alignment
apparatus characterized by excellent alignment performance,
especially for curled sheets. This sheet alignment apparatus
ensures excellent alignment of the paper, independently of the
presence or absence of curling or the degree of curling.
[0063] The aforementioned embodiments provide a sheet alignment
apparatus characterized by excellent alignment performance and
compact structure.
[0064] The aforementioned embodiments provide a sheet finisher
capable of producing a booklet characterized by preferably aligned
edges of sheets.
[0065] The aforementioned embodiments allow the process of binding
to be applied to the bundle of sheets with aligned edges, thereby
ensuring an improved quality of bound documents.
* * * * *